Metathesis chemistry has been widely used in the synthesis of high molecular weight polymers and other materials. In the presence of transition metal-catalysts, including commercially available ruthenium-based Grubbs-type carbenes and molybdenum-based and tungsten-based Schrock alkylidenes, olefins can exchange groups around double bonds via metallocyclobutane intermediates to form new double bonds. Olefin metathesis employs carbon-carbon double bonds, which may typically be unreactive toward other reagents, as the reactive functional groups. In some cases, metathesis reactions may be performed in the presence of a wide variety of functional groups and under mild conditions, such as at room temperature.